A-Axis Yba2cu3o7-Delta/Au Interface Conductance-Voltage Characteristics

Conductance-voltage characteristics of interfaces between a-axis YBa2Cu3O7-delta (YBCO) thin films and gold are presented. When the gold counter electrode is deposited in-situ, the junctions have a specific interface resistivity in the 10(-9) Omega-cm(2) range, about an order of magnitude lower than nominal in-situ, c-axis YBCO/noble-metal junctions. As with nominal c-axis YBCO/noble-metal junctions, there is clear evidence at T = 4 K for a peak in the conductance at low bias. In addition, a dip in the middle of the broad peak structure was resolved. It appears to be a feature unique to the a-axis YBCO/Au interface.